f2fs: fix to avoid race in between aio and gc

We won't wait DIO synchronously when doing AIO, so there will be potential
IO reorder in between AIO and GC, which will cause data corruption.

This patch adds inode_dio_wait to serialize aio and data GC to avoid this
issue.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/gc.c

@@ -875,6 +875,9 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 					continue;
 				}
 				locked = true;
+
+				/* wait for all inflight aio data */
+				inode_dio_wait(inode);
 			}
 
 			start_bidx = start_bidx_of_node(nofs, inode)